I have been using Firefox 50.1.0 and yesterday I downloaded pcxFirefox-50.1.0-enUS-vc2015-x64-sse2-betterpgo-161213

Questions:

1)How to correctly install on my computer?

****I opened the .zip file on my desktop but their is no install button. I pressed the firefox.exe (included in the package) and it opened firefox...but in the "about firefox" tab, it doesn't say anything about pcxFirefox. There is also no pcxFirefox in C:programs.....just the regular version.

I am new to custom fireFox builds, so sorry if these questions seem stupid. I have searched the web for hours to find more info about pcxFirefoxm but I can NOT find answers to the many questions I have, such as...

2) once pcxFirefox is correctly installed, can I then delete the regular version of Firefox?